Process for polymerization of olefins and catalyst composition therefor

ABSTRACT

A process for polymerizing Alpha -olefins in the presence of a Ziegler catalyst, such catalyst comprising (i) a pulverulent catalyst component obtained by mechanically or physically copulverizing a halogen compound of low valency titanium obtained by reducing titanium tetrahalide with a member selected from the group consisting of hydrogen, metallic aluminum and metallic titanium, an oxide selected from the group consisting of (a) an oxide selected from the group consisting of MgO, Al2O3 and SiO2 and (b) a compound oxide containing at least two elements selected from the group consisting of Mg, Al and Si, in an inert atmosphere in the solid phase until the average particle size of the pulverized product reaches 5 microns or less; and (ii) an organoaluminum or organozinc compound.

United States Patent 1 Tomoshige et al.

[ 1 Feb. 27, 1973 [75] lnventors:T0ru Tomoshige, lwakuni; Shiro Honma,Otake, both of J apan [73] Assignee: Mitsul Petrochemical Industries,Ltd. Tokyo, Japan 22] Filed: Dec. 14, 1970 [21] Appl. No.: 98,197

[30] Foreign Application Priority Data Dec. 16, i969 Japan ..44/l00605[52] US. Cl. ..260/93.7, 252/429 C, 260/882 R, 260/949 DA, 260/949 E[51] Int. Cl. ..C08f l/56, C08f 3/10 [58] Field of Search "260/937, 94.9DA, 94.9 E

[56] References Cited UNITED STATES PATENTS 3,072,628 l/l963 Coover etal. ....260/93.7 3,483,269 12/1969 Magoon et al ..260/683.15 3,168,4842/1965 Engel et al ..260/94.9 3,594,330 7/1971 Delbouille et al...260/94.9

FOREIGN PATENTS OR APPLICATIONS 1,560,602 2/1969 France 601 ,9l9 7/ 1960Canada Primary Examiner-Harry Wong, Jr. Assistant ExaminerEdward J.Smith AttorneySherman and Shalloway [57] ABSTRACT A process forpolymerizing molefins in the presence of a Ziegler catalyst, suchcatalyst comprising (i) a pulvetulent catalyst component obtained bymechanically or physically copulverizing a halogen compound of lowvalency titanium obtained by reducing titanium tetrahalide with a memberselected from the group consisting of hydrogen, metallic aluminum andmetallic titanium, an oxide selected from the group consisting of (a) anoxide selected from the group consisting of MgO, A1 0 and SiO; and (b) acompound oxide containing at least two elements selected from the groupconsisting of Mg, Al and Si, in an inert atmosphere in the solid phaseuntil the average particle size of the pulverized product reaches 5microns or less; and (ii) an organoaluminum or organozinc compound.

8 Claims, No Drawings PROCESS FOR POL'YMERIZATION OF OLEFINS ANDCATALYST COMPOSITION THEREFOR This invention relates to an improvedprocess for polymerization of olefins and a catalyst composition for usein the process. More specifically, the invention relates to an improvedprocess for polymerizing or copolymerizing a-olefins having three toeight carbon atoms or copolymerizing such olefin with ethylene withimproved isotacticity and specific polymerization activity (the yield ingrams of polymer per milligramatom of titanium atom per hour and peratmospheric pressure: g/mg-atom.hr.atm.), and to an improved catalystcomposition for use in the practice of this process.

It has been known to polymerize or copolymerize aolefins in an inertsolvent in the presence of a Ziegler catalyst comprising a halogencompound of low valency titanium and an organoaluminum or organozinccompound.

The present invention is an improvement of such process for polymerizinga-olefins with an improved catalyst composition comprising i. apulverulent catalyst component obtained by mechanically copulverizing ahalogen compound of low valency titanium obtained by reducing titaniumtetrahalide with a member selected from the group consisting ofhydrogen, metallic aluminum and metallic titanium, and at least oneoxide selected from the group consisting of (a) an oxide selected fromthe group consisting of MgO, A1 and SiO and (b) compound oxidescontaining at least two elements, selected from the group consisting ofMg, Al and Si, in an inert atmosphere in the solid phase until theaverage particle size of the pulverized product reaches 5 p. or less,

and

ii. an organoaluminum or organozinc compound.

Some proposals have been known to utilize an inert carrier in thepolymerization or copolymerization of olefins using Ziegler catalysts.

British Patent specification No. 815,805 discloses an improved processfor polymerizing an a-olefin, which comprises contacting a gascomprising the a-olefin with finely divided solid particles comprising aZiegler catalyst and an inert solid carrier material in the substantialabsence of a liquid solvent or diluent. The British patent cites suchinert solid carriers as finely divided silica, titanium oxide, clays inanhydrous pulverulent or granular form such as diatomaceous earth,finely divided asbestos and-glass fibers, sodium chloride, sodiumsulfate, calcium carbonate, calcium oxide, finely divided solidparticles of the polymer such as polystyrene, which is different fromthe polymer to be polymerized thereon. It is described that when theorgano-metal composition is solid, the solid organo-metal compositioncan be admixed in finely divided form with the silica particles andblended therewith, for example, by mechanical agitation or grinding.

This British specification, however, is quite silent with respect to thegrinding of the solid halogen compound of low valency titanium and thesolid carrier in the solid phase, the extent of such grinding, theusability of the resulting catalyst comprising the titanium componentand the organo-metallic compound ground in the solid phase for thepolymerization of olefins in an inert solvent and in liquid phase, andthe superiority of using such catalyst. The patent only gives anexperimental example in which ethylene was polymerized in the absence ofa polymerization solvent using a catalyst obtained by admixingtriisobutyl aluminum dissolved in liquid pentane and titaniumtetrachloride dissolved in liquid pentane with diatomaceous earth,sodium chloride or polystyrene in finely ground and dry form andthereafter completely evaporating pentane.

In the present invention, the solid halogen compound of low valencytitanium and a solid carrier should be copulverized in the solid phaseand to the extent such that the average particle size of the pulverizedproduct is diminished to 5 p. or less. The objects of the presentinvention cannot be achieved if a catalyst composition prepared underthe copulverizing conditions outside those specified above is used.Furthermore, the use of a mixture of an average particle size of 5 p. orless consisting of separately pulverized solid halogen compound of lowvalency titanium and solid carrier or the use of a catalyst compositionprepared in the absence of a carrier cannot lead to the achievement ofthe objectives of the present invention. These will be demon strated inComparative Examples which will appear later in the specification.

Accordingly, the present invention can be distinguished from BritishPat. No. 815,805 in that the invention consists essentially ofcopulverizing the particles until the specific particle sizes areattained, which is not referred to the British patent specification, andthat the polymerization of the invention is limited to one in thepresence of a sufficient amount of an inert solvent or liquid a-olefin,preferably liquid propylene, whereas the British Patent, to one in theabsence of an inert polymerization solvent or in the presence of a verysmall amount of it.

British pat. specification Nos. 907,579 and 910,261 disclose theproduction of a rubbery polymer or copolymer having an atactic structureand a low crystallinity in which a Ziegler catalyst in finely dividedstate is admixed with one or more inert, solid diluents, preferably toform a fluidized bed, and an olefinically unsaturated hydrocarbon ispolymerized in the gas phase and in the absence of a liquid phase. Thepatents exemplify such solid diluents as silica gel, kieselguhr,alumina, metal oxides such as calcium oxide or magnesium oxide, andsalts such as calcium carbonate.

These two British patents do not disclose nor suggest thecopulverization of a solid halogen compound of low valency titanium anda solid carrier in the solid phase, the extent of the copulverization,the usability of the resulting catalyst comprising titanium componentground in the solid phase and the organo-metal compound for thepolymerization of olefins in an inert solvent or in liquid phase, andthe superiority of using such catalyst. Moreover, the product is arubbery atactic polymer having substantially no isotacticity.

U. S. Pat. No. 3,166,542 proposes a process for polymerizing olefinsusing a catalyst comprising a transition metal compound and anorgano-metallic compound, the transition metal compound being preparedby reacting a halogen compound of a transition metal of Groups 4A to 6Aof the periodic table with a pulverulent inorganic solid having ahydroxyl group on the surface such as magnesium oxide is directedaluminum oxide or silicon oxide in a substantially anhydrous conditionat 105C. or below while removing a gas formed the by-product during thereaction, thereby to chemically fix the halogen compound of thetransition metal onto the surface of the inorganic solid.

The U. S. patent, however, only gives an example of liquid-phasereaction to fix the halogen compound of the transition metal chemicallyonto the inorganic solid, and generally discloses no solid-phasereaction. In other words, this patent illustrates only the use ofsolution on liquid halogen compounds of transition metals, and onlyteaches the use of a titanium component prepared by bonding a halogencompound of a liquid or gaseous transition metal chemically onto apulverulent inorganic solid having an average particle size of less thanl ;.i.. There is no disclosure or suggestion as to the use of a titaniumcomponent obtained by copulverization of a solid titanium compound and asolid carrier in the solid phase.

The results illustrated hereinafter show, as described of the firstproposal, that the object of the present invention cannot be achieved ifa carrier pulverized previously is admixed with a titanium compoundpulverized alone.

Belgian Pat. No. 705,220 proposes a process for polymerizing a-olefinsusing a catalyst comprising a complex and an organometallic compound,the complex being prepared by reacting a halogen derivative of atransition metal of Groups 4A to 6A of the Periodic Table with an oxideof a divalent metal in the absence of a diluent and in an anhydrouscondition with small amounts of hydroxyl groups. This process, however,does not prove useful for polymerizing a-olefins to highly crystallinepolymers, because the liquid halogen derivative of the transition metalis employed, and the chemical bonding of the halogen derivative to theoxide carrier is performed in the liquid phase different from the solidphase in the invention.

It has now been found that polymers or copolymers of a-olefins havingthree to eight carbon atoms or copolymers of such a-olefins withethylene with high isotacticity are produced with good specificpolymerization activity using an organo-aluminum or organo-zinc compoundand a titanium component obtained by copulverizing a solid halogencompound of low valency titanium and at least one solid oxide selectedfrom the group consisting of (a) an oxide selected from MgO, M and SiO,and (b) compound oxide containing at least two elements selected fromthe group consisting of Mg, Aland Si, in the solid phase to thespecified particle size.

A primary object of this invention is to a process for producing homoorco-polymers of C -C a-olefins or copolymers of such a-olefins withethylene having improved isotacticity with improved specificpolymerization activity using a catalyst comprising the organoaluminumor organozinc compound and the titanium component which can be obtainedby simple means of good reproducibility.

Another object of the invention is to provide a catalyst compositionwhich is easy to prepare and is suitable for the production of homoorco-polymers of Cy-C a-olefins having improved isotacticity and withimproved specific polymerization activity.

Many other objects and advantages of the invention will become apparentfrom the following description.

The pulverulent titanium component used in the invention is obtained bymechanically or physically copulverizing a halogen compound of lowvalency titanium obtained by reducing titanium tetrahalide with a memberselected from the group consisting of hydrogen, metallic aluminum andmetallic titanium and at least one oxide selected from the groupconsisting of (a) an oxide selected from the group consisting of MgO, AlO and SiO and (b) compound oxides containing at least two elementsselected from the group consisting of Mg, Al and Si in the solid phasein an inert atmosphere until the average particle size of the pulverizedproduct reaches 5 u or less.

Optical microscopic photographs of the pulverized product indicate thatthis solid-phase copulverization can readily lead to a reduction inaverage particle size of the oxide selected from MgO, A1 0 and SiOand/or compound oxides containing at least two of Mg, Al and Si.

As the halogen compound of low valency titanium, trivalent titaniumcompound obtained by reducing titanium tetrachloride with anorganometallic compound such as an organoaluminum compound did notproduce good results.

The mechanism of improving the activity of a halogen compound of lowvalency titanium is not clear, but it is assumed that there is someother important factor than the effect of mere copulverization, since ithas been confirmed, as previously stated, that the objects of thepresent invention cannot be achieved when a pulverulent mixture ofseparately pulverized halogen compound of low valency titanium andinorganic oxide selected from magnesia, alumina and silica and/orcompound oxides containing at least two of Mg, Al and Si is used.

The inorganic oxide selected from MgO, M 0 and SiO and/or compoundoxides containing at least two of Mg, Al and Si is preferably deprivedof water by drying or calcination. More preferably from the viewpoint ofincreasing the yield of polymer per unit weight of titanium atom, theinorganic oxide, prior to use, is treated with an organic compound of ametal of Groups 2 to 3 of the Periodic Table, preferably anorganoaluminum or organozinc compound in an inert hydrocarbon solventsuch as hexane maintained at 0 to l50C., washed with an inerthydrocarbon solvent such as hexane, and then dried.

Such pretreatment is performed by contacting the inorganic oxide withthe organometallic compound in an inert hydrocarbon solvent such assaturated aliphatic hydrocarbons having flve to 16 carbon atoms, forinstance, pentane, hexane, heptane, kerosene and cyclohexane, usually ata temperature of 0 to C. for a period of time from 0.5 to 4 hours. Ifdesired, the contacting is effected with stirring. As the organometalliccompound suitable for such pre-treatment, the following can be cited,for example, trialkyl aluminums having an alkyl group with one to sixcarbon atoms, dialkyl aluminum halides having an alkyl group with one tosix carbon atoms, alkyl aluminum dihalides having an alkyl group withone to six carbon atoms, alkyl aluminum sesquihalides having an alkylgroup with one to six carbon atoms, and dialkylzincs having an alkylgroup with one to four carbon atoms. Specific examples include triethylaluminum, tributyl aluminum, triisobutyl aluminum, trihexyl aluminum,diethyl aluminum chloride, diethyl aluminum bromide, ethyl aluminumsesquichloride, ethyl aluminum dichloride, diethylzinc, and dibutylzinc.

In the co-pulverization treatment of the invention, the amount of thehalogen compound of low valency titanium is preferably in the range of0.1 to 2.0 millimols per gram of the oxide.

Any means for effecting the copulverization in the solid phase can beused which is capable of pulverizing the solid mixture to an averageparticle size of 5 or less, preferably to such a size that at least 80percent by weight of the total particles have a particle size of 5 a orbelow. Usually, the average particle size of the pulverized product isin the range of 0.1 to 5 [.L.

The copulverization may be effected by means of a vibratory ball mill,rotary ball mill, tube mill, disc-type vibratory mill, and jet impactpulverizer. Pulverization with a ball mill is most popular, anddesirable. There is no particular restriction on the copulverizationtemperature, but usually from room temperature to 130C., preferably fromroom temperature to 60C. The pulverizing time is chosen depending uponthe method of pulverization and the material to be pulverized, but inshort, the copulverization may be continued until the average particlesize of the magnesium oxide, aluminum oxide or silicon oxide and/orcompound oxides containing at least two of Mg, Al and Si reaches 5 p. orless. For this purpose, the pulverization time is usually from 5 to 50hours. The effect of copulverization is observed even if the averageparticle size does not reach the above-specified value, but such is notsufficient.

The copulverization and the washing, recovery and transportation, etc.of the copulverized product are usually and preferably carried out in asubstantially anhydrous condition in an atmosphere of an inert gas suchas nitrogen or argon. There is no need at all to use a liquid diluent inthe co-pulverization treatment, and the use of it is often undesirable.

in the present invention, a catalyst composed of the componentcopulverized in the manner described and an organoaluminum or organozinccompound is used. As the organometallic compound, the following can becited, for instance, trialkyl aluminums having an alkyl group with oneto six carbon atoms, dialkyl aluminum halides having an alkyl group withone to six carbon atoms, dialkyl aluminum alkoxides where in the alkylgroup has one to six carbon atoms and the alkoxy group having one tofour carbon atoms, alkyl aluminum alkoxy halides wherein the alkyl grouphas one to six carbon atoms and the alkoxy group has one to four carbonatoms, and dialkylzincs having an alkyl group with one to four carbonatoms. Specific examples include triethyl aluminum, tributyl aluminum,trihexyl aluminum, triisobutyl aluminum, diethyl aluminum chloride,diethyl aluminum bromide, diethyl aluminum ethoxide, and ethyl aluminumethoxychloride. One can also employ the reaction products of alkylaluminum dihalides or alkyl aluminum sesquihalides with electron donorssuch as phosphines, ethers and esters, the reaction products of saidalkyl aluminum halides with fluoro-complexes containing an alkali metalof Group 4 of the periodic table such as alkali metal titanium fluoride,or the reaction products of said reaction products with alkenylmonoethers.

The process of the invention is suited particularly for thepolymerization or copolymerization of a-olefins having three to eightcarbon atoms or the copolymerization of such a-olefins with ethylene inan inert solvent or liquid or-olefin. Examples of such aolefins includepropylene, l-butene, 4-methyl-l-pentene, and l-hexene. Specifically, theprocess is used conveniently for the production of homopolymers ofpropylene, l-butene, 4-methyl-l-pentene and l-hex ene, and copolymers ofpropylene, l-hexene, or 4- methyl-l-pentene with ethylene or l-butene.For obtaining a highly crystalline copolymer from ethylene andpropylene, it is necessary to adjust the ethylene content of theresulting copolymer to 30 mol percent or less.

The process of the present invention can be performed in the same way asin the known polymerization or copolymerization of a-olefins using aZiegler catalyst in an inert solvent, such as an inert hydrocarbonsolvent or liquified a-olefin, preferably hexane or liquefied propylene.

For example, the polymerization can be performed by putting thecopulverized solid catalyst component prepared above and anorganoaluminum or organozinc compound in a suitable inert hydrocarbonsolvent such as hexene, heptane or kerosene, or liquefied a-olefin in acondition substantially free from catalyst poison such as oxygen orwater, and then introducing an a-olefin thereinto. The polymerizationthat can be generally used ranges from 20 to 250C. or so, preferably 40to 150C. The polymerization pressure is from atmospheric pressure toabout Kg.cm g, preferably 2 to 60 Kg/cm g. The concentration of thecopulverized fine solid catalyst component is suitably from 0.005 to 10g per liter of the solvent, and the concentration of the organo-metalliccompound is preferably from 0.01 to 50 m-mols per liter of the solvent.

The molecular weight adjustment of the a-olefin polymer can be effectedby changing the polymerization temperature, the combination of thecatalyst components and the molar ratios of the catalyst components, butcan effectively performed by adding hydrogen to the polymerizationsystem. ltis also possible to increase the yield and apparent density ofthe polymer by adding silicon oil, esters, etc. to the polymerizationsystem.

According to the process of the present invention, highly stereoregularpolymers or copolymers of C;,C a-olefins or copolymers of such a-olefinswith ethylene can be obtained with high specific polymerizationactivity.

The nresent invention will be described below further with reference toworking examples together with several comparative examples, all ofwhich are in no way intended to limit the invention.

In the following examples, the halogen compound of low valency titaniumand the inorganic oxide were copulverized in the solid phase under thefollowing standard conditions unless otherwise specified.

A 400 ml. stainless or porcelain cylindrical ball mill having an innerdiameter of 10 cm was used. The diameter each of stainless or porcelainballs used was 10 to mm, and the total volume of all balls was 100 ml.The inorganic oxide and the halogen compound of low valency titaniumwere placed in the ball mill, and copulverized in the solid phase atroom temperature at 100 rpm. The content of titanium atom in theresulting product was determined by polarography.

Unless otherwise specified, the polymerization was performed under thefollowing standard conditions in all of the following examples.

A 2-liter stainless steel autoclave equipped with a stirrer having twoblades was used. One liter of refined hexane, the halogen compound oflow valency titanium copulverized as described above, and anorganoaluminum or organozinc compound were fed into the autoclave, andafter raising the temperature to 65C., an olefin was introduced at aconstant pressure of 7 Kg/cm and polymerized for 3 hours. Aftercompletion of the polymerization, the polymer obtained was transferredto another vessel. Hexane was removed by distillation with steam, andthe polymer was dried for 16 hours under vacuum at 80C. The isotacticityindex which is a measure for the stereoregularity of an aolefin polymerwas indicated as a residue of the polymer extracted for 24 hours withhot n-heptane.

The number average particle size of the inorganic oxide and thecopulverized solid catalyst prepared by using it was measured by usingan optical microscope (product of Nippon Kogaku Kogyo Kabushiki Kaisha,Japan) with 70 magnifications. For convenience of operation, thematerial to be measured was suspended in kerosene.

EXAMPLE 1 AND COMPARATIVE EXAMPLES 1 TO 3 Silicon oxide (MSJD gel;product of Fuji-Davison Chemical Ltd.) was dried for 2 hours at 200C. inan atmosphere of nitrogen in a quarz tube. The dried silicon oxide had aspecific surface area of 300 m /g and an average particle size of 50 u.Eighty grams of the dried silicon oxide and 21 g of titanium trichloride(reduced with metallic aluminum; to be referred to AA hereinafter;product of Toho Titanium Company LTD.) were pulverized for 20 hoursunder the standard conditions in a ball mill. The catalyst contained52.7 mg of titanium per gram thereof, and had an average particle sizeof 5 ;1.. Using 1,000 mg of this solid catalyst and 3 millimols ofdiethyl aluminum chloride, the polymerization of propylene was performedfor 3 hours under the standard conditions. The yield of polypropylenewas 94 g per milligram atom-of titanium, and it had an isotacticityindex of 86 percent.

For comparative purposes, the procedure of the foregoing Example I wasrepeated except that a solid catalyst component having an averageparticle size of 20 p. was used with the shortened pulverization time(Comparative Example 1); the procedure of Example 1 was repeated exceptthat silicon oxide and titanium trichloride were separately pulverized,and then mixed to form the solid catalyst component (Comparative Example 2); and the procedure of Example I was repeated except that onlypulverized titanium trichloride was used with the ommission of siliconoxide (Comparative Example 1). The results obtained are given in thefollowing Table l.

TABLE 1 Solid catalyst Organo- Polypropylene component (average metalllcparticle size in p.) component A B C copulverized product Ex. 1 (5 p)ofSiO, and (C,H ),AlCI 94 86 4.5

TiCl, (AA) Comp. ditto (20 p.) ditto 68 90 3.2 Ex. 1 Comp. Mixture (5p.) of ditto 60 92 2.9 Ex. 2 pulverized SiO,

and pulverized 'l'iCl, (AA) Comp. Pulverized TiCl, ditto 64 90 3.0 Ex. 3(AA) (51 Yield in grams ofpolymer per milligram-atom of titanium.lsotacticity index. Specific polymerization activity.

EXAMPLE 2 Magnesium oxide (product of Kyowa Chemicals Co., Ltd., Japan)was put in a quarz tube, and calcined for 1 hour at 700C. in anatmosphere of nitrogen. The calcined magnesium oxide had a specificsurface area of 28 m /g and an average particle size of 20 p. Forty-twograms of the dried magnesium oxide and 10 g of titanium trichloride (AA,product of Toho Titanium Co., Ltd., Japan) were pulverized for 20 hoursunder the standard conditions in a ball mill. The solid catalystobtained had a titanium content of 53.2 mg per gram thereof, and anaverage particle size of 5 t. Using 2,036 mg of the solid catalyst and 3millimols of diethyl aluminum chloride, propylene was polymerized in oneliter of hexane under the standard conditions for 3 hours. The yield ofpolypropylene was 90 g per milligram-atom of titanium, and thepolypropylene had an isotacticity index of 88 percent.

For comparative purposes, the procedure of the foregoing Example 2 wasrepeated except that the solid catalyst component was used which had anaverage particle size of 5 t and was prepared by mixing 1,000 mg of thecalcined magnesium oxide above which was pulverized at room temperaturefor 20 hours at rpm in a ball mill and 220 mg of titanium trichloride(AA) pulverized for 43 hours at room temperature at 120 rpm in a ballmill, together with 3 millimols of diethyl aluminum chloride(Comparative Example 4); and the procedure of Example 2 was repeatedexcept that 100.6 mg of pulverized titanium trichloride (AA) was used(Comparative Example 5). The results obtained are given in Table 2.

verized TiCl ,(AA) Comp. Ex.

Pulvcrized TiCl,(AA)

(5 p.) ditto 64 90 30 Yield (q/mq-atom) [.1 Sp. Activity (q/mq-atom. hr.atom) EXAMPLE 3 One liter of hexane was put into an autoclave, and theinside of the autoclave was purged with nitrogen. The solid catalystcomponent obtained by copulverization of titanium trichloride andmagnesium oxide (prepared by the method of Example 1) (2050 mg), 3millimols of diethyl aluminum chloride and 250 g of 4- methyl-1-pentene(purity 96 percent) were fed successively. The temperature was raised to60C., and the polymerization of 4-methyl-l-pentene was performed for 3hours. The polymerization was stopped by addition of 40 ml. of methanol,and the resulting polymer was precipitated in liters of methanol. Afterfiltration, the cake was dried under vacuum for hours at 80C. to yieldpo1y-4-methyl-1-pentene in an amount of 25 g per milligram atom oftitanium. The polymer had an isotacticity index of 93 percent.

For comparative purposes, the procedure of the foregoing Example 3 wasrepeated except that 4- methyl-l-pentene was polymerized using 605 mg ofpulverized titanium trichloride (prepared by the process of ComparativeExample 4) and 3 millimols of diethyl aluminum chloride (ComparativeExample 6).

The results obtained are given in Table 3.

TABLE 3 Solid catalyst Organo- Poly-4-methy1- component (averagemetallic l-pentane particle size in p.) component A B C copulverizedproduct Ex. 3 (511.) of MgO and (C,H ),AlCl 25 93 8.3

TiCl,(AA)

Comp. ulverized Ex. 6 TiCI (AA) (5 ll.) ditto 13 95 4.3

' Yield (q/mq-atom) 1.1. "Sp. activity (q/mq-atom. hr. atm.)

COMPARATIVE EXAMPLE 7 The inside of an autoclave was purged withnitrogen, then 1 liter of kerosene, 3 millimols of triisobutyl aluminum,and 200 mg of a solid catalyst component (prepared by the method ofExample 2) by copulverization of magnesium oxide and titaniumtrichloride (AA) were put into the autoclave. Hydrogen was introduced toa partial pressure of 3.5 Kg/cm g, and the temperature was raised to90C. The stirrer was rotated at a rate of 350 rpm. Ethylene wasintroduced continuously so that the total pressure was maintained alwaysat about 7 Kg/cm -g, and subjected to suspension polymerization for 2hours. The suspension of polymer obtained was thoroughly washed withhexane, and dried under vacuum for 15 hours at C. to yield polyethylene.The polymer had an apparent density of 0.18 g/ml. and a specificpolymerization activity of 69.3 g/milligram-atom of titanium.hr.atm.

COMPARATIVE EXAM PLE 8 Ethylene was polymerized in the same way as inComparative Example 7 using 38 mg of titanium trichloride (AA) (productof Toho Titanium, Co. Ltd., Japan) and 3 m-mols of triisobutyl aluminum.The resulting polyethylene had an apparent density of 0.18 g/mL, a meltindex of 0.2, and a specific polymerization activity of 71g/mg-atom.hr.atm.

COMPARATIVE EXAMPLE 9 Fifty grams of commercial magnesium oxide (with aspecific surface area of 40 m /g), which had been dried for 1 hour at300C, was dispersed in 300 ml. of kerosene, and millimols of titaniumtetrachloride were added. While the temperature was being maintained at0C. with stirring, 87 millimols of ethyl aluminum sesquichloride wereadded dropwise over a period of 1 hour. After completion of theaddition, the mixture was heated to 40C. and aged for 5 hours. Aftercompletion of the reaction, the resulting product was transferred onto aglass filter, washed throughly with dehydrated hexane, and dried toyield a red brown solid powder. Analysis indicated that 62.9 mg oftitanium atom had been deposited per gram of this solid. Using 1,130 mgof the resulting solid catalyst, and 3 millimols of diethyl aluminumchloride, propylene was polymerized under the standard conditions. Theresulting polymer was formed only in a trace amount.

EXAMPLES 4 to 7 Fifty grams of magnesium oxide (product of KyowaChemicals, Japan; specific surface area 40 m /g, average particle size10 IL), which had been calcined for 2 hours at 600C. in an atmosphere ofnitrogen, were pre-treated with about 200 millimols of either triethylaluminum, diethyl aluminum chloride, ethyl aluminum dichloride ordiethylzinc in 200 ml. of kerosene for 3 hours at C. with stirring. Thepretreated product was then washed with hexane, and dried. About 40 geach of these four kinds of magnesium oxides pre-treated with theorgano-metallic compound and titanium trichloride (AA, product of TohoTitanium, Japan) were copulverized in a ball mill for 20 hours under thestandard conditions. The solid catalyst component obtained had anaverage particle size of 0.5.

Using 1,000 mg of the solid catalyst component and 3 millimols ofdiethyl aluminum chloride, propylene was polymerized for 3 hours underthe standard conditions to yield polypropylene.

The results obtained are given in Table 4.

(grams) Ll.

pre-treatcomponent ment (mg/g- Examples cat. comp.)

4 E Al 40 I40 89 6.7 5 Et,A Cl 46 I18 90 5.6 6 EtAlCl 50 I00 88 4.8 7 ETZn 45 I33 89 6.3

Note: ET' stands for ethyl group.

COMPARATIVE EXAMPLE l0 Sixty-four grams of titanium trichloride (AA,product of Toho Titanium Co., Ltd., Japan) and 2.70 g of diethylaluminum chloride were pulverized in a ball mill for 20 hours at roomtemperature employing the standard conditions described before. Using acatalyst composed of 418 mg of the resulting pulverized product havingan average particle size of 2 p. and 3 millimols of diethyl aluminumchloride, propylene was polymerized for 3 hours under the standardconditions to yield polypropylene. The yield of polypropylene was 78 gper milligram-atom of titanium, and it had an isotacticity index of 91percent and a specific polymerization activity of 3 .7g/mgatom.Ti.hr.(I(g/cm EXAMPLE 8 Fifty grams of 'y-aluminum oxide(product of Wako Pure Chemical, Industries, Ltd. Japan), which had beendried for 2 hours at 300C. in an atmosphere of nitrogen were pretreatedwith 20 ml. of diethyl aluminum chloride in 200 ml. of kerosene for 3hours with stirring. After completion of the treatment, the aluminumoxide was washed with hexane, and dried to yield a dried product havingan average particle size of t. Forty grams of the dried aluminum oxideobtained and 100 g of titanium trichloride (AA, product of Toho TitaniumCo., Ltd., Japan) were mixed with each other, and pulverized in a ballmill for hours under the standard conditions. The titanium content pergram of the solid catalyst component obtained was 47.0 mg, and theaverage particle size of the catalyst was 2 t. Using 2,005 mg of thissolid catalyst component and 3 millimols of diethyl aluminum chloride,propylene was polymerized for 3 hours under the standard conditions toyield polypropylene. The yield of polypropylene was 135 g per milligramatom of titanium, and it had an isotacticity index of 91 percent and aspecific polymerization activity of 6.4 g/mgatom.hr.(Kg/cm EXAMPLE 9Forty grams of silica gel obtained by pretreating 50 g of the driedsilicon oxide of Example I with 100 millimols of triethyl aluminum inthe same way as in Example 4, and 10.7 g of 8-titanium trichloride (AA,product of Toho Titanium Co., Ltd., Japan) were pulverized in a ballmill for 20 hours under the standard conditions. The titanium contentper gram of the solid catalyst component was 41.6 mg, and its averageparticle size was 0.9 IL. Using 2,018 mg of this solid catalyst and 3millimols of diethyl aluminum chloride, propylene was polymerized for 3hours under the standard conditions to yield polypropylene. The yield ofpolypropylene was 164 g per milligram atom of titanium, and it had anisotacticity index of 93 percent and a specific polymerization activityof 7.8 g/mg-atom Ti.hr.(I(g/cm COMPARATIVE EXAMPLE ll Forty-five gramsof a powdery product obtained by pretreating magnesium oxide (product ofKyowa Chemicals Co., Ltd., Japan) with a specific surface area of 52 m/g which had been obtained by drying for 3 hours at 180C. in a tube inan atmosphere of nitrogen, with triethyl aluminum in the same way as inExample 4, and 4.7 g of S-titanium trichloride (AA, product of TohoTitanium Co., Ltd., Japan) were mixed, and pulverized in a ball mill for20 hours under the standard conditions. The titanium content per gram ofthe solid catalyst component was 29.] mg, and its average particle sizewas 0.7 u, Using 985 mg of this solid catalyst component and 3 millimolsof diethyl aluminum chloride, propylene was polymerized for 3 hoursunder the standard conditions. The yield of polypropylene was 3.6 permilligram-atom of titanium, and it had an isotacticity index of 63percent and a specific polymerization activity of 1.7 g/mg-atomTi.hr.(Kg/cm EXAMPLE 10 Using 3 millimols of diethyl aluminum chloride,and 2,005 mg of a solid catalyst component obtained in accordance withthe procedure of Example 4 by copulverizing magnesium oxide pretreatedwith triethyl aluminum and titanium trichloride, 4-methyl-l-pentene waspolymerized in the same way as set forth in Example 3 to formpoly-4-methyl-l-pentene in an amount of 30 g per milligram-atom oftitanium. The polymer obtained had an isotacticity index of 95 percentand a specific polymerization activity of 10.0 g/mg-atom Ti.hr.(Kg/cmEXAMPLE l 1 One hundred grams of silicon oxide (MS-ID gel) dried underthe conditions of Example l were suspended in 500 ml. of refined hexane,and were reacted with 50 millimols of triethyl aluminum under reflux for3 hours, followed by filtration and drying. The pretreated silicon oxide(63 g) and 11.5 g of hydrogen-reduced titanium trichloride (product ofStauffer Chemical Corp.) were pulverized for 48 hours under the standardconditions. The titanium content per gram of the solid catalystcomponent obtained was 47.1 mg, and its average particle size was 0.8 a.Using l,0l0 mg of this solid catalyst component and 3 millimols ofdiethyl aluminum chloride, propylene was polymerized for 3 hours underthe standard conditions. Polypropylene was obtained in an amount of 90 gper milligram-atom of titanium, and the polymer had an isotacticityindex of percent.

COMPARATIVE EXAMPLE 12 The dried silicon oxide prepared in Example 2 wasdispersed in 500 ml. of N -purged, dehydrated kerosene, with theaddition of 250 millimols of TiCl The dispersion was cooled to 0C. Ethylaluminum sesquichloride (250 millimols) was added dropwise with goodstirring. After completion of the addition,

the mixture was heated to 40C., and aged for 3 hours. The resultingbrown slurry was filtered in an atmosphere of nitrogen, washed with dryhexane, and dried. About 40 g of the resulting solid catalyst componentwere pulverized in a ball mill for 20 hours under the standardconditions. The titanium content of the solid catalyst component pergram thereof was 45.] mg, and its average particle size was 3 t.

Using 1,010 mg of the solid catalyst component and 3 millimols ofdiethyl aluminum chloride, propylene was polymerized for 3 hours underthe standard conditions to yield polypropylene in an amount of 51 g permilligram-atom of titanium, which had an isotacticity index of 58percent.

EXAMPLE l2 Silica-alumina (product of Mizusawa Kagaku Kogyo KabushikiKaisha, Japan) containing 10 percent of silica component was predriedfor 3 hours at 400C. in a quarz tube to form a dried product having aspecific surface area of 350 mlg.

One hundred grams of this dried product were treated with 150 millimolsof triethyl aluminum in 100 ml. of kerosene for 2 hours at 80C.,followed by filtration, washing with hexane and drying. Fifty grams ofsilica-alumina so treated and 16 g of TiCl (AA) were pulverized in aball mill for 30 hours under the standard conditions. The titaniumcontent of the resulting solid catalyst component was 56.8 mg per gramthereof, and the average particle size was 1 ;1..

Using 533 mg of the solid catalyst component and 3 millimols of diethylaluminum chloride, propylene was polymerized for 3 hours under thestandard conditions. The yield of polypropylene was 127 g permilligramatom of titanium, and its isotacticity index was 93 percent.

EXAMPLE 13 A glass ampoule containing l,000 mg of the titaniumtrichloride composition of Example 1 was'placed in a 2- liter stainlessautoclave equipped with an electromagnetically operated stirrer andcapable of withstanding pressure up to I Kg/cm G in such a way that theampoule would be destroyed simultaneously with the rotation of thestirring rod and the contents fall into the autoclave. The inside of theautoclave was thoroughly purged with nitrogen. Diethylaluminum chloridemillimols) was added, and 460 g of liquid propylene and then hydrogen at26 Kglcm fi were introduced into the autoclave. The reaction mixture washeated to 60C., and stirring was initiated. The ampoule was broken, andthe polymerization began. The polymerization was continued for 1 hour at60C. After completion of the reaction, unreacted propylene was removedby flushing, and the catalyst was removed by decomposition with additionof methanol. The product was dried under reduced pressure to form 183 gof a polymer (which corresponded to 165 g per millimol of Ti). Thepolymer had an isotacticity index of 93 percent.

What is claimed is:

l. A process for polymerizing or copolymerizing aolefins having three toeight carbon atoms or copolymerizing said a-olefins with ethylene in aninert solvent or a liquid a-olefin in the presence of a Ziegler catalystcomprising i. a pulverulent catalyst component obtained by mechanicallyor physically copulverizing a solid halogen compound of low valencytitanium obtained by reducing titanium tetrahalide with a memberselected from the group consisting of hydrogen, metallic aluminum andmetallic titanium, and at least one solid oxide selected from the groupconsisting of (a) an oxide selected frmm the group consisting of MgO, M0 and SiO and (b) a compound oxide containing at least two elementsselected from the group consisting of Mg, Al and Si, in an inertatmosphere in the solid phase until the average particle size of thepulverized product reaches 5 to 0.1 1., the amount of said halogencompound of low valency titanium being in the range of 0.1-2.0 millimolsper gram of said oxide; and

ii. an organo-metallic compound selected from the group consisting of(a) a trialkyl aluminum having an alkyl group of one to six carbonatoms; (b) a dialkyl aluminum halide having an alkyl group with one tosix carbon atoms; (0) a dialkyl aluminum alkoxide wherein the alkylgroup has one to six carbon atoms and the alkoxy group has one to fourcarbon atoms; (d) an alkylaluminum alkoxy halide wherein the alkyl grouphas one to six carbon atoms and the alkoxy group has one to four carbonatoms; (e) a reaction product of an alkyl aluminum dihalide or an alkylaluminum sesquihalide with an electron donor; (f) the reaction productof an alkyl aluminum dihalide or an alkyl aluminum sesquihalide with afluoro-complex containing an alkali metal of Group IV of the PeriodicTable; (g) the reaction product of reaction products (e) or (f) with analkenyl monoether; and (h) a dialkylzinc having an alkyl group with oneto four carbon atoms.

2. The process of claim 1, wherein said oxide has been pre-treated bycontact with a compound selected from the group consisting of trialkylaluminums having an alkyl group with one to six carbon atoms, dialkylaluminum halides having an alkyl group with one to six carbon atoms,alkyl aluminum dihalides having an alkyl group with one to six carbonatoms, alkyl aluminum sesquihalides having an alkyl group with one tosix carbon atoms, and dialkylzincs having an alkyl group with one tofour carbon atoms.

3. The process of claim 1, wherein said a-olefin having three to eightcarbon atoms is selected from the group consisting of propylene,l-butene, 4-methyl-lpentene and l-hexene.

4. The process of claim 1, wherein the polymerization orcopolymerization is carried out at a temperature in the range of 20 to250C.

5. The nrocess of claim 1, wherein the polymerization orcopolymerization is carried out at a pressure ranging from atmosphericpressure to 100 Kg/cm -g.

6. The process of claim 1, wherein the amount of said pulverulentcomponent is in the range of 0.005 to 10 g per liter of said inertsolvent or liquid a-olefin.

7. The process of claim 1, wherein the amount of the organometalliccomponent of the catalyst is in the range of 0.01 to 50 millimols perliter of said inert solvent or liquid a-olefin.

8. The process of claim 1, wherein at least percent of the pulverizedparticles have diameters within the range of5 to 0.1 [1,.

2. The process of claim 1, wherein said oxide has been pre-treated bycontact with a compound selected from the group consisting of trialkylaluminums having an alkyl group with one to six carbon atoms, dialkylaluminum halides having an alkyl group with one to six carbon atoms,alkyl aluminum dihalides having an alkyl group with one to six carbonatoms, alkyl aluminum sesquihalides having an alkyl group with one tosix carbon atoms, and dialkylzincs having an alkyl group with one tofour carbon atoms.
 3. The process of claim 1, wherein said Alpha -olefinhaving three to eight carbon atoms is selected from the group consistingof propylene, 1-butene, 4-methyl-1-pentene and 1-hexene.
 4. The processof claim 1, wherein the polymerization or copolymerization is carriedout at a temperature in the Range of 20* to 250*C.
 5. The process ofclaim 1, wherein the polymerization or copolymerization is carried outat a pressure ranging from atmospheric pressure to 100 Kg/cm2-g.
 6. Theprocess of claim 1, wherein the amount of said pulverulent component isin the range of 0.005 to 10 g per liter of said inert solvent or liquidAlpha -olefin.
 7. The process of claim 1, wherein the amount of theorganometallic component of the catalyst is in the range of 0.01 to 50millimols per liter of said inert solvent or liquid Alpha -olefin. 8.The process of claim 1, wherein at least 80 percent of the pulverizedparticles have diameters within the range of 5 to 0.1 Mu .